Dense propellant containing fluoropolymers and heavy metal component

ABSTRACT

A dense propellant composition for use in the first stage rocket engine of a multistaged missile system. The composition comprises Viton A, Teflon, mercuric oxide, and uranium-aluminum alloy.

United States Patent [191 I Dierolf [451 Aug. 21, 1973 {73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: Nov. 24, 1971 [21] Appl. No.: 203,109

[52] US. Cl 149/19, 149/44, 149/87 [51] Int. Cl C066 5/06 [58] Field of Search 149/19, 44, 87

[56] References Cited UNITED STATES PATENTS 3,198,678 8/1965 Zeman et a1 149/44 3,640,070 2/1972 Kaufman et a1. 149/19 X 3,317,362 5/1967 Doris et a1. 149/44 X 3,463,682 8/1969 l-lamrick 149/19 3,513,043 5/1970 Burnside 149/87 3,634,153 1/1972 Perkins 149/44 X 3,671,343 6/1972 Gawlick 149/38 X Primary Examiner-Carl D. Quarforth Assistant Examiner-E. A. Miller Attorney- R. S. Sciascia and Roy Miller [57] ABSTRACT A dense propellant composition for use in the first stage rocket engine of a multistaged missile system. The composition comprises Viton A, Teflon, mercuric oxide, and uranium-aluminum alloy.

3 Claims, No Drawings DENSE PROPELLANT CONTAINING FLUOROPOLYMERS AND HEAVY METAL COMPONENT BACKGROUND OF THE INVENTION The invention relates to a dense propellant composition.

The prior art methods of increasing propellant performance places emphasis on increasing specific impulse. This tends to result in higher flame temperatures, increased propellant sensitivity, and considerable condensed combustion products, all of which tend to reduce reliability of the rocket motor. Present vuseful dense propellants have impact sensitivities of less than 110 kg-cm. This improved composition has a lower flame temperature and less sensitivity than most of the conventional ones known today. Thermal stability is comparable to the conventional dense propellants.

BRIEF DESCRIPTION OF INVENTION The invention is for a dense propellant composition that will give maximum performance in single stage and first stage rocketengines. The composition is simple to manufacture and relatively economical. In accordance with the present invention Viton-A is dissolved in acetone to percent concentration) and added to an open mix pot. While agitating the mixture, Teflon and mercuric oxide is added to form a slurry. Uraniumaluminum alloy is then added and mixed. The Viton-A is shocked-gelled or precipitated onto the solids in the slurry by the addition, with agitation, of hexane in a ratio of about 4:1 hexane to acetone. The slurry is washed several times with hexane, and after each addition, agitation is stopped and the hexane is decanted. After the final wash, the material is removed from the mix pot and placed on stainless steel drying trays. The hexane is allowed to evaporate partially in air at ambient temperature, then the material is placed into an oven at 110 180 F. to complete drying.

In preparing this composition it should be emphasized that flame-resistant clothing, safety shoes, and safety shields should be utilized at all times.

The preferred composition comprises Percent by weight Ingredients Viton-A 9.3 Teflon 4.7 Mercun'c oxide 67.0 Uranium-aluminum powder (5-70 microns, 19.0

mean particle size) (UAl2) 0.10 in/sec at 1,000 psia. The pressure exponent is very low in the pressure range of 200 1,000 psia. The calculated flame temperature is 5,500 F.

This invention discloses that a dense propellant can be formulated with a flame temperature of 5,500 F. by using a dense inert diluent such as mercury or lead in combination with a dense reactive material such as uranium-aluminum alloy, or the aluminum alloys of thorium or zirconium. The diluent soaks up the heat while the reactive ingredient furnishes enough energy to give a measured density times specific impulse product of 700 gm/sec/cc of propellant. By using a very dense metal oxidizer which decomposes in the temperature range of 250 l,000 C. such as mercuric oxide, whose metal decomposition-product boils at a temperature lower than the rocket exhaust temperature, a binder containing fluorine, and a heavy metal alloy whose fluorides also boil at a temperature lower than the nozzle exhaust temperature, an all gaseous nozzle flow is possible (except for some solid aluminum oxide in the case of heavy metal-aluminum alloys). Any carbon present is oxidized to carbon monoxode which is a gas at room temperature. The dense inert metal from the decomposed oxidizer and the heavy metal fluoride combustion products act as heat sinks to soak up the combustion energy. The result is an all gaseous nozzle flow, a low flame temperature, and a high specific impulse-density product. Thus, an increase in propellant sensitivity or flame temperature is not necessary for increased performance.

Reactive metal alloys which produce stable gaseous oxides or fluorides at combustion temperatures are potential candidates for this new dense propellant composition. Other heavy metal oxidizers may be used. Binders containing fluorine, solid and stable at 250 C. are possible alternate binders.

What is claimed is:

l. A propellant composition comprising:

a binder consisting of a mixture of the copolymer of vinylidene fluoride and hexafluoropropylene and polytetrafluoroethylene;

a mercuric oxide diluent; and

an uranium-aluminum alloy.

2. The composition in accordance with claim 1 wherein the copolymer of vinylidene fluoride and hexafluoropropylene consists of 9.3 percent by weight;

the polytetrafluoroethylene consists of 4.7 percent by weight;

the mercuric oxide consists of 67 percent by weight;

and

the uranium-aluminum consists of 19 percent by weight.

3. The composition in accordance with claim 2 wherein the uranium-aluminum alloy has a mean particle size ranging from 5 70 microns. 

2. The composition in accordance with claim 1 wherein the copolymer of vinylidene fluoride and hexafluoropropylene consists of 9.3 percent by weight; the polytetrafluoroethylene consists of 4.7 percent by weight; the mercuric oxide consists of 67 percent by weight; and the uranium-aluminum consists of 19 percent by weight.
 3. The composition in accordance with claim 2 wherein the uranium-aluminum alloy has a mean particle size ranging from 5 -70 microns. 